In recent years, surface mount ceramic electronic components (for example, a ceramic inductor by using magnetic ceramic, a ceramic capacitor by using dielectric ceramic, a ceramic piezoelectric component by using piezoelectric ceramic, and the like), which is mounted by soldering external electrodes formed on the surface of a ceramic element assembly to lands disposed on a wiring board on the basis of a method, e.g., by way of reflow soldering, or the like, have been used widely.
However, pores are present in the surface of the ceramic element assembly, which is a sintered body, and flux contained in solder is absorbed into the pores of the ceramic element assembly during soldering. As a result, each granular solder is melted as-is while the fine granular shape is kept and a continuous liquid having fluidity is not formed. Therefore, a problem occurs in that a self alignment property (a characteristic in which molten solder arrives in a gap and the like between an external electrode and a land and, thereby, a ceramic electronic component is mounted at a predetermined position, e.g., on the land of a mount board, reliably) is degraded. In addition, a problem occurs in that the reliability in connection between an external electrode and a land is degraded.
Meanwhile, from the viewpoint of promoting solderability of the external electrode, for example, formation of a plating film has been widely performed (e.g., a Ni plating film or a Sn plating film on an Ag electrode serving as an external electrode main body (substrate layer)). However, there is a problem in that a plating solution, wash water, and the like infiltrate into the inside of a ceramic element assembly during a plating step and, thereby, electrical characteristics are degraded. To solve this problem, a method for manufacturing an electronic component has been proposed where an organosilicon compound is formed through dehydration-condensation on a ceramic element assembly surface, pore portions opened at the surface, and external electrodes. See, Japanese Unexamined Patent Application Publication No. 10-214741 (Patent Document 1).
In this regard, it is mentioned that according to this method, infiltration of a plating solution, water, and the like into the inside of the ceramic element assembly is prevented and, thereby, degradation of the electrical characteristics can be suppressed.
Furthermore, regarding the soldering technology used in mounting of a ceramic electronic component, a composition containing a polymer including a polymerization unit of an unsaturated ester having a polyfluoroalkyl group, a fluorine based surfactant, and an aqueous medium has been proposed as a composition to prevent solder flux wicking. See, Japanese Unexamined Patent Application Publication No. 11-154783 (Patent Document 2).
In this regard, it is mentioned that in the case where this composition is used, absorption of the flux into pores of the ceramic element assembly during soldering can be prevented.